added --peek-skip-errors flag #1

- Does not fully solve #1 but helps debug why iperf3 or ping might fail
- Lets the script continue testing other peer MTUs in the loop
- added an additional ping check every time the peer MTU is changed to flush the connection

README.md

@@ -55,6 +55,7 @@ Install the following on both the WG server and WG peer
 1. The project assumes that you already have a working WG installation on both the WG peer and WG server.
 1. The project assumes that you already have a WG interface like `wg0`.
 1. The project assumes that you already have a WG conf file like `/etc/wireguard/wg0.conf`. ***Take a backup of these files***.
+1. Before running the following scripts, the WG interface is expected to be active/online such that the peer is able to ping the server.    
 1. Start the WG server script before the WG peer script
 
 ### On the WG Server

nr_wg_mtu_finder/main.py

@@ -5,6 +5,7 @@ import sys
 from pydantic import BaseModel, StrictStr, StrictInt, root_validator
 from typing_extensions import Literal
 from .mtu_finder import MTUFinder
+from distutils.util import strtobool
 
 
 def signal_handler(sig, frame):
@@ -30,6 +31,8 @@ class ArgsModel(BaseModel):
     server_ip: StrictStr
     server_port: int = 5000
 
+    peer_skip_errors: bool = True
+
     interface: StrictStr = "wg0"
     conf_file: StrictStr = "/etc/wireguard/wg0.conf"
 
@@ -94,6 +97,13 @@ def setup_args():
         required=False,
         default="/etc/wireguard/wg0.conf",
     )
+    parser.add_argument(
+        "--peer-skip-errors",
+        help="Skip errors when an expected error occurs in peer mode during MTU loop.",
+        required=False,
+        default=True,
+        type=strtobool,
+    )
     args = parser.parse_args()
     return args
 

nr_wg_mtu_finder/mtu_finder.py

@@ -10,9 +10,22 @@ from nr_wg_mtu_finder.sync_server import run_sync_server
 from nr_wg_mtu_finder.plot import plot_log
 
 
+class ReturncodeError(Exception):
+    pass
+
+
 class MTUFinder(object):
     def __init__(
-        self, mode, server_ip, server_port, interface, conf_file, mtu_max, mtu_min, mtu_step
+        self,
+        mode,
+        server_ip,
+        server_port,
+        interface,
+        conf_file,
+        mtu_max,
+        mtu_min,
+        mtu_step,
+        peer_skip_errors,
     ):
         """Init."""
         self.mode = mode
@@ -30,6 +43,8 @@ class MTUFinder(object):
         self.server_mtu = None
         self.current_mtu = None
 
+        self.peer_skip_errors = peer_skip_errors
+
         self.log_filename = (
             f"wg_mtu_finder_{self.mode}_{datetime.now().strftime('%Y%m%dT%H%M%S')}.csv"
         )
@@ -62,6 +77,21 @@ class MTUFinder(object):
             )
         print("SUCCESS")
 
+    @staticmethod
+    def handle_returncode(returncode, stdout, stderr):
+        """Handle status code."""
+        if returncode == 0:
+            print("SUCCESS")
+        else:
+            print(f"FAILED with code {returncode}")
+            print(f"*" * 80)
+            print(f"STDOUT:\n-------")
+            print(stdout)
+            print(f"STDERR:\n-------")
+            print(stderr)
+            print(f"*" * 80)
+            raise ReturncodeError()
+
     def append_log_with_bandwidth_info(self, up_rcv_bps, up_snd_bps, down_rcv_bps, down_snd_bps):
         """Append the bandwidth information to the log file."""
         if self.mode == "server":
@@ -93,7 +123,7 @@ class MTUFinder(object):
             universal_newlines=True,
         )
         stdout, stderr = process.communicate()
-        print("SUCCESS" if process.returncode == 0 else f"FAILED with code {process.returncode}")
+        self.handle_returncode(returncode=process.returncode, stdout=stdout, stderr=stderr)
 
     def wg_quick_up(self):
         """Spin up the interface using wg-quick."""
@@ -106,7 +136,7 @@ class MTUFinder(object):
             universal_newlines=True,
         )
         stdout, stderr = process.communicate()
-        print("SUCCESS" if process.returncode == 0 else f"FAILED with code {process.returncode}")
+        self.handle_returncode(returncode=process.returncode, stdout=stdout, stderr=stderr)
 
     def __validate_conf_file(self):
         """Validate that a line `MTU =` exists in the wireguard conf."""
@@ -137,7 +167,7 @@ class MTUFinder(object):
         )
 
         stdout, stderr = process.communicate()
-        print("SUCCESS" if process.returncode == 0 else f"FAILED with code {process.returncode}")
+        self.handle_returncode(returncode=process.returncode, stdout=stdout, stderr=stderr)
 
     def run_iperf3_upload_test(self):
         """Run iperf3 upload test."""
@@ -151,8 +181,7 @@ class MTUFinder(object):
 
         # Wait iperf3 test to be done.
         stdout, stderr = process.communicate()
-
-        print("SUCCESS" if process.returncode == 0 else f"FAILED with code {process.returncode}")
+        self.handle_returncode(returncode=process.returncode, stdout=stdout, stderr=stderr)
 
         # load iperf3 output json which results from the -J flag
         output = json.loads(stdout)
@@ -174,8 +203,7 @@ class MTUFinder(object):
 
         # Wait iperf3 test to be done.
         stdout, stderr = process.communicate()
-
-        print("SUCCESS" if process.returncode == 0 else f"FAILED with code {process.returncode}")
+        self.handle_returncode(returncode=process.returncode, stdout=stdout, stderr=stderr)
 
         # load iperf3 output json which results from the -J flag
         output = json.loads(stdout)
@@ -243,8 +271,7 @@ class MTUFinder(object):
         )
 
         stdout, stderr = process.communicate()
-
-        print("SUCCESS" if process.returncode == 0 else f"FAILED with code {process.returncode}")
+        self.handle_returncode(returncode=process.returncode, stdout=stdout, stderr=stderr)
 
     def run_peer_mode(self):
         """Run all steps for peer mode.
@@ -291,13 +318,28 @@ class MTUFinder(object):
 
                 # Wait a short while after interface is spun up.
                 time.sleep(1)
-                up_rcv_bps, up_snd_bps = self.run_iperf3_upload_test()
-                time.sleep(1)
-                down_rcv_bps, down_snd_bps = self.run_iperf3_download_test()
 
-                self.append_log_with_bandwidth_info(
-                    up_rcv_bps, up_snd_bps, down_rcv_bps, down_snd_bps
-                )
+                try:
+                    # Ping IP address of server to flush connection
+                    self.__peer_mode__ping_server()
+
+                    up_rcv_bps, up_snd_bps = self.run_iperf3_upload_test()
+                    time.sleep(1)
+                    down_rcv_bps, down_snd_bps = self.run_iperf3_download_test()
+
+                    self.append_log_with_bandwidth_info(
+                        up_rcv_bps, up_snd_bps, down_rcv_bps, down_snd_bps
+                    )
+                except ReturncodeError:
+                    if self.peer_skip_errors:
+                        print(
+                            "Caught ReturncodeError. --peer-skip-errors is set to True. "
+                            "Continuing with other peer MTUs. Bandwidth for this MTU will be "
+                            "recorded as -1."
+                        )
+                        self.append_log_with_bandwidth_info(-1000000, -1000000, -1000000, -1000000)
+                    else:
+                        raise
 
     def run_iperf3_server_test(self):
         """Run iperf3 upload test."""

nr_wg_mtu_finder/plot.py

@@ -75,10 +75,3 @@ def plot_log(log_filename, plot_filename):
     f.suptitle("Peer MTU vs Server MTU Bandwidth (Mbps)")
     f.tight_layout()
     f.savefig(plot_filename, dpi=300)
-
-
-if __name__ == "__main__":
-    plot_log(
-        "/home/nitred/projects/group-nr/nr-wg-mtu-finder/examples/example.csv",
-        "/home/nitred/projects/group-nr/nr-wg-mtu-finder/examples/example.png",
-    )